fix(k8s): run mount compatibility check on skip-cluster-management path too

The mount-compatibility check lived inside create_cluster(), which only
runs under --perform-cluster-management. Under the (default)
--skip-cluster-management path the check was skipped — a deployment
joining an existing cluster with an incompatible kind-config would
proceed and silently fall through to the node's overlay FS, which is
exactly the failure mode the check was designed to catch.

Rename _check_mounts_compatible → check_mounts_compatible (now public)
and call it from both paths in _setup_cluster().

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

stack_orchestrator/deploy/k8s/deploy_k8s.py

@@ -26,6 +26,7 @@ from stack_orchestrator.deploy.deployer import (
     DeployerException,
 )
 from stack_orchestrator.deploy.k8s.helpers import (
+    check_mounts_compatible,
     create_cluster,
     destroy_cluster,
     get_kind_cluster,
@@ -818,6 +819,12 @@ class K8sDeployer(Deployer):
                     "fresh cluster (note: destroys the existing one if "
                     "names collide)."
                 )
+            # Mount topology applies regardless of who owns cluster
+            # lifecycle — validate here too.
+            kind_config = str(
+                self.deployment_dir.joinpath(constants.kind_config_filename)
+            )
+            check_mounts_compatible(existing, kind_config)
         self.connect_api()
         self._ensure_namespace()
         if self.is_kind() and not self.skip_cluster_management:

stack_orchestrator/deploy/k8s/helpers.py

@@ -278,7 +278,7 @@ def _get_running_cluster_mounts(cluster_name: str) -> Dict[str, str]:
     }
 
 
-def _check_mounts_compatible(cluster_name: str, config_file: str) -> None:
+def check_mounts_compatible(cluster_name: str, config_file: str) -> None:
     """Fail if the new deployment's extraMounts aren't active on the cluster.
 
     Kind applies extraMounts only at cluster creation. When a deployment
@@ -370,7 +370,7 @@ def create_cluster(name: str, config_file: str):
     existing = get_kind_cluster()
     if existing:
         print(f"Using existing cluster: {existing}")
-        _check_mounts_compatible(existing, config_file)
+        check_mounts_compatible(existing, config_file)
         return existing
 
     _warn_if_no_umbrella(config_file)